Recalling their marriage, Ronald Reagan's first wife had one overriding memory of his personality in private: "Ronnie never shut up". And the same applies to his letter writing, judging by a collection of 5,000 pieces of correspondence from the former president, published this week. They embrace everything from his guilt about sex, his love of Snoopy, to a personal appeal to the Soviet leader Leonid Brezhnev to not let philosophical differences get in the way of their jobs.

He also told Hugh Hefner, the publisher of Playboy, that he believed communists in the United States did not deserve free speech.

Reagan was known to his supporters as the great communicator, but his critics saw a man who slept through meetings, and who was - in the words of his sympathetic biographer, Edmund Morris - "an apparent airhead".

The letters reveal a more complex picture, of a president not always focusing on politics, but who seemed to take much more interest in the nuts and bolts of the job than many have supposed.

"My Dear Mr President, I regret and yet can understand the somewhat intemperate tone of your recent letter," he wrote to Brezhnev while recovering from an assassination attempt. "After all, we approach the problems confronting us from opposite philosophical points of view. It is possible that we have let ideology...keep us from considering the very real, everyday problems of the people we represent?" Aides attempted to prevent him sending the letter, and the state department drafted an alternative version. Reagan sent both.

"Even in marriage I've had a little guilty feeling about sex, as if the whole thing was tinged with evil," he wrote to a friend who had sought his advice. But then he had been told about the behaviour of Polynesian islanders, he went "These people who are truly children of nature and thus of God, accept physical desire as a natural, normal appetite."

Reagan: A Life in Letters is published in the United States on Tuesday, and extracts are included in today's edition of Time magazine. Much of the correspondence was discovered when Kiron Skinner, a university professor, happened upon the letters while researching a book on the cold war.

"The American Communist," Reagan wrote to Playboy founder Hugh Hefner, "is bound by party discipline to deny he is a community so that he can by subversion and stealth impose on an unwilling people the rule of the International Communist Party which is in fact the government of Soviet Russia."

And yet, in his dealings with Soviet Russia, Reagan - now 92 and suffering from Alzheimer's disease - often seemed less confrontational than he was in public. Besides the Brezhnev letter, there is a note to a friend in which Reagan denies trying to develop the star wars anti missile system to use as a bargaining chip in relations with Moscow. "I did tell Gorbachev that if and when we had such a system they would join us in eliminating nuclear missiles; we'd share such a defence with them," he insisted. "I don't think he believes me."

"It's important to understand that Reagan, unconscious of being anthologised one day... addressed all these letters to individual people, who reactions were important to him," Mr Morris wrote, reviewing the book in the Washington Post.

In 1978, Reagan engaged in argumentative correspondence with a pastor who had apparently said he did not believe in the literal divinity of Jesus. "Either he was what he said he was, or he's the world's greatest liar," Reagan thundered, discounting the latter suggestion.

Reagan's daughter Patti Davis, writing in Time today, remembered a father often more forthcoming in his letters than in person.

"It's odd to think that the man who has been called the 'great communicator' was often shy with others, yet it's true," she wrote.